Drafting instrument.



W. G) GLASSON.

DRAFTING INSTRUMENT. APPLICATION FILED JULY 31, 1912.

Patented Feb. 10, 1914.

WALTER G. CLASSON, OF LEOMINSTER, MASSACHUSETTS.

DRAFTING INSTRUMENT.

LQSGAMP.

To all 207mm it may concern Be it known that I, VALTER G. CLAssoN, a citizen of the United States, residing at Leominster, county of *Worcester, State of Massachusetts, have invented an Improve- .ment in D 'afting Instruments, of which the following description, in connection wit-h the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to drafting instruments of that type which are used by draftsmen in drawing curves of different radius, and the object of the invention is'to provide a novel device of this character which is simple in construction and easy to adjust, and by means of which either regular or irregular curves of any desired radius can be drawn.

Another object of the invention is to provide an instrument of this nature in which the ruler portion has such a construction that one end thereof can be adjusted to either a straight line or a curve of one character, while the other end can be adjusted to present a curve of an entirely different charaeter.

My invention is especially useful in railroad work, for by means of it the engineer can readily lay out a railroad curve of any required radius. The device, however, is equally well adapted for general use.

Referring now to the drawings wherein I have illustrated the preferred embodiment of my invention, Figures 1 and 2 show plan views of the device adjusted to present dif ferent curves; Fig. 3 is an enlarged section on the line m m, Fig. 2; Fig. 4 is an enlarged section on the line yg Fi g. 2.

My improved device comprises a base portion 1, a ruler member 2 and curve-determining members 3 which provide an adjustable connection between the ruler portion and the base and by which the ruler is adjusted to present the desired curve.

While the base 1 may have any suitable shape I prefer that herein shown wherein it presents an approximately semi-circular periphery 4t to which the ruler member 2 is secured. I will preferably make the base skeleton shape in order to make the instru ment lighter, although this is not essential.

In the drawings the base presents the approximately semi-circular rim portion 5 and the diametrical cross portion 6, these two being connected by the radial portion 7, the

Specification of Letters Patent.

Application filed July 31, 1912.

Patented Feb. fit 191st. Serial No. 712,418.

edge 8 of which is on a true radius of the peripheral curve i and is preferably aranged at right angles to the diametrical portion 6. This edge 8 may conveniently be graduated ininches or any other units of measure.

The ruler member 2 is a flexible member to permit it to be readily bent into a curvature of the desired shape. This member 2 is secured to the periphery 4L of the base at a. point intermediate of its ends, and in the preferred embodiment of my invention I secure the ruler member to said periphery at the point 9. The two ends 10 and 11 of the ruler member are capable of being independently adjusted to different curves by means of the curve-determining members 3. These members are secured at one end to the ruler member and each is of a length to overlie the base and is provided with acurved slot 12 through which extends aclamping screw secured to the base, said screw being provided with a clamping nut 14. These curve-determining members are V secured to the ruler member at different points along its length and each curve-determining member is independent from every other member and can be independently adjusted. I will preferably make each curve-determining member with the beveled face 15 which will be provided with graduations marked to indicate the radii of different curves and the rim portion 5 of the base will preferably be provided with index marks 16, one for each of the curve-determining members 3. The curve-determining members may be secured to the ruler member in any suitable way. As herein shown each curve-determining member has a pin 17 screwed into the end thereof, which pin extends through the ruler member 2 and is secured therein by a cross pin 18. The clamping screws 13 are also anchored in the base by means of a locking pin 19.

In the construction shown in the drawings the slots 12 are of such a length that when the curve-determining members are adjusted to bring the lower ends of the slots against the clampin screws 13. as seen in full lines Fig, 1, the ruler member will as sume a straight line tangent to the peripheral curve 1. If it is desired to adjust the ruler member 2 throughout its extent to a regular curve of a given radius, the clamping nuts 14 are loosened, and each of the curve-determining members is adjusted inwardly until the graduation mark indicating the desired radius comes opposite the corresponding index mark 16. The ruler member can be clamped in this position by tightening up the clamping nuts 14, as will be obvious. If again it is desired to draw a curve of a given radius which merges into a tangential line, then one end, the end 11, for instance, of the ruler member, may be adjusted to the straight line position shown in Fig. 1, and the other end 10 adjusted to the desired curvature, as shown in dotted lines. If, again, it is desired to adjust the ruler member to present an irregular curve, then the curve-determining members can be independently adjusted to get the required curvature in the ruler member, as clearly seen at the right, Fig. 2.

One of the important features of my invention is that the two ends of the ruler member can be independently adjusted to present different curves and that the curvedetermining members 3 are all independent from each other.

I prefer to graduate the outer face of the ruler member. The graduations may be in any units of measure, but preferably will be in inches. The advantage of this is that the person using the instrument can readily scale the length of the arc.

It will be noted that the edge 8 of the radial portion 7 is in a true radial line drawn through the point of the convex periphery 4 at which the ruler member is attached. The advantage of this construction is that it enables a person to readily draw parallel curves, for if after the ruler member is adjusted for any particular curve, and said curve is drawn, it is desiredto draw another curve parallel thereto, the draftsman merely draws a line along the edge 8 and then shifts the base 1 longitudinally of said line but keeping the edge 8 on the line until the ruler member has been carried the proper distance away from the first mentioned curve, but parallel thereto, after which the second curve, parallel to the first can be drawn.

\Vhile I have illustrated the preferred embodimentof my invention, I do not wish to be limited to the constructural details shown.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is In a device of the class described, the combination with a base having a conveXly curved periphery, of a flexible ruler member connected centrally to the periphery of the base, a plurality of separate and independent cur-vedetermining members con nected to the ruler member, and independent means for adjustably connecting each curve-determining member to the base.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WALTER Gr. CLASSON.

VVit-nesses:

LOUIS 0. SMITH, THOMAS J. DRUMMOND.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

